Combined biostimulation and bioaugmentation for chlorpyrifos degradation in laboratory microcosms.

Chlorpyrifos (CP) is a persistent organophosphorus pesticide (OP) used in soil ecosystem for insect control. Bioremediation process has been proven promising in degrading these toxic molecules and restoring the physio-chemical properties of soil. This work reports a laboratory microcosm study in both non-sterile & sterile conditions, conducted over a period of 56 days to examine the combined effect of additional supplements like biostimulants (BSs) such as N, P, and K in the presence of suitable carrier materials (compost, wheat straw, and corncob) along with bioaugmentation by a Ochrobactrum sp. CPD-03 on CP degradation from the contaminated soil. CP degradation was thoroughly monitored at an interval of 7 days over a period of 56 days. Results showed biostimulation and bioaugmentation along with compost as carrier material had shown higher CP degradation efficiency of 76 ± 2.8 and 74 ± 1.6% in non-sterile and sterile microcosms over a period of 56 days. Moreover, bacterial community profiling (16s rRNA and opd gene) demonstrated increased microbial counts, corroborating the efficiency of the bioremediation process. The survival of CPD-03 at the end of the assay validated its ability of colonizing modified soils. By this integrated method with compost as carrier material, bioremediation process could be enhanced for restoration CP-contaminated soils.